P3D v4 Flatten or not [solved]


I release the CYYY airport scenery built with FSX SDK. It well displays on FSX. But not in P3Dv4.

View attachment 47619
Look the scenery in this screen send to me by a P3D pilot. You see the taxis and the end of the main runway (at left of the Maule's left wing). The scenery have a Flatten Exclude Autogen that covers all this runway.

I dont have P3D installed and dont plan for install it. What I have to do to make the scenery P3Dv4 compatible with FSX SDK?

Yep, I think Tom might be on it. You might also ask Arno his thoughts. This happened with me on importing to FSX from FS2004 tech scenery. You might also need to use multiple 'flatten zones'. I forget what we did to fix mine. Arno worked on it. It was like 12 or 15 years ago. I cannot remember what we did exactly.


Resource contributor
It would seem the terrain elevation in your PV4 is different from that in FSX. Lionheart, this is also generally true between FS9 and FSX; FSX mesh is more detailed than FS9 mesh.

The PV4 stock mesh appears to be the same as FSX. So, Jean Pierre, I suspect you have non-stock mesh installed in either FSX or PV4, or perhaps in both but different meshes. In your screenshot, it also appears your flatten elevation is much too low for the terrain

Your flatten must be compatible with the mesh with which it is to be used. In undulating terrain matching ARP elevation, terrain elevation and terrain can be a real "bear". That's why in most of my airports I've made extensive use of sloping polys in the "flatten" (which is then no longer flat).

Thanks for your replies.

The scenery was entirely made with FSX tools (FSDS 3.5 linked on FSX SDK for the objects, ADE 1.7 linked on FSX SDK for the airport).

I repeat that in FSX the scenery display very well, in FSX default or third party meshes for FSX.

So if I understand I have to add a bigger and higher flatten zone to be compatible with P3Dv4.


Resource contributor
So if I understand I have to add a bigger and higher flatten zone to be compatible with P3Dv4
Doesn't matter what tools you used to create the airport. In hilly country, a single, horizontal flatten won't work - unless you are happy with cliffs somewhere along the edge. Your flatten needs to have the same elevation at its edges as the terrain it meets.

Higher and bigger will help. But, you probably need to add a few sloping flattens as well.

Did you use ADE to change the airport elevation? Did you copy across the small bgl file it puts into scenery/world/scenery (will have airport code in the filename). It will be in your fsx folder so it works in fsx. If missing from p3d, you can get that in the trench effect.
Thank you for your opinion gentlemen. Unfortunately I made you work for nothing because my tester had forgotten to disable his ORBX meshes scenery. In basic configuration, my FSX scene displays perfectly in P3Dv4.
Wonderful! No-m you did not make us work for nothing. We're all one family and family always helps.

yep- when sending your scenery, if you changed elevation of your AFCAD the ALT file is always done for you, BUT you have to include that ALT file in the stuff you send. It is iin scenery\world\scenery as Gadgets said. And sloped polys are often desirable around the edges and such... and fun to do as well. Oh- and don't forget ground polys in ADE. I think Gadgets developed that. Yes/no? We can do ground polys without the old flickering! Wish someone could adress my FSDS Tweak issue. The builder exterior screen shows up twice which renders my end work un usable.